Modern vehicles may include a plurality of antennas and probes. These protrusions add additional drag to the vehicle, increase the potential for fluid transfer through the hull of the vehicle, decrease the structural integrity of the hull of the vehicle, and are prone to breakage. In the case an aircraft vehicle, the pressure differential between ambient and internal may increase the potential for fluid transfer with each hull orifice. Many systems require redundant antenna installations to ensure safety, reliability, and/or availability. For example, an aircraft vehicle may be required to maintain two to three VHF antenna elements mounted external to the aircraft skin. Regulatory requirements may demand at least two of these elements be operational before flight to ensure redundant VHF capability.
Additional systems and initiatives (Next Generation Air Transportation System (NextGen), Systems Engineering 2020 (SE-2020), Single European Sky ATM Research (SESAR)) are pushing for additional systems which may require additional antennas and receivers. Conversely operators are desirous to reduce drag and weight to reduce fuel costs and boost profits. Each of these additional systems requires an undesirable additional antenna or multiple antennas mounted to the external of the vehicle.
Antenna addition to a vehicle may include factors which increase cost, decrease structural integrity, and decrease vehicle performance. For example, regulatory requirements for antenna addition to an aircraft may prove time consuming and costly. An additional penetration of the skin of an aircraft may require additional structure to maintain the integrity of the pressure hull.
Each skin penetration of a vehicle may degrade a performance capability of the vehicle. For example, a penetration of a pressure hull of an aircraft may have long term adverse effects on structural integrity over the lifetime of the pressure hull. In addition, each penetration of the aircraft pressure hull may require exhaustive testing and evaluation combined with regulatory approval before an operator may execute the additional skin penetration.
Each additional antenna placement may further degrade performance of the vehicle. For example, an additional antenna placed external to the hull of an aircraft may increase parasitic drag leading to increased fuel burn, decreased range and ceiling, and decreased overall performance of the aircraft. Further, additional cables routed from antenna elements through the aircraft to avionics systems increase overall weight and reduce aircraft performance.
Traditionally, phase ambiguity (N) has been resolved by using more than one baseline (three or more antennas) where the baseline differences are less than or equal to half of the signal wavelength. These traditional methods may typically use progressive unambiguous baseline difference combinations to ultimately resolve the ambiguity number of the longest (most accurate) baseline. These traditional methods suffer from the requirement of multiple antennas to accomplish accurate resolution of the ambiguity number.
In addition, cosite interference between antenna elements may preclude optimal operation of the antenna reception. As additional antenna elements may be installed, undesirable additional interference may preclude original antenna performance.
Therefore, a need remains for a system and related method enabling currently installed antenna elements to receive and analyze an RF signal creating the novel ability to relatively locate the transmitter of the RF signal.